Spherical rod ends are often used when rotary motion is to be converted into reciprocating motion. One example is with a friction curtain apparatus of a vehicle wash, such as that disclosed in U.S. Pat. No. 4,096,600. A motor is used to rotate a crank arm which is connected by a spherical rod end to a connecting rod whose other end is attached to the first ends of a pair of pivot arms. The pivot arms, in turn, are pivotally attached along their mid-lengths to a transverse rod or axis with the far ends of the pivot arms supporting a rack which has friction curtains suspended therefrom. When the crank arm rotates through 360.degree. , the ends of the pivot arms reciprocate forward and backward with the curtains imparting a sweeping, scrubbing or flicking motion to clean a vehicle passing through the vehicle wash.
The crank arm is affixed to a spherical ball on the spherical rod end with the ball pivoting within a race surface of a housing. Pivoting of the ball relative to the race surface may cause friction therebetween and annoying squeaking noise. To reduce friction and the associated noise problem, lubrication is provided to the spherical rod end.
Spherical rod ends are available with grease fittings which pass grease from a grease gun to the interface between the race surface and the ball. However, several problems exist if this type of lubrication is used with a friction curtain apparatus in a vehicle wash. First, only a small quantity of grease can be stored in the spherical rod end. Therefore, it is necessary that the grease fitting be repeatedly filled with grease. Also, as a vehicle wash is typically a soapy environment, the grease is easily broken down and lost. The motor and its crank arm are generally located in a position high above the floor, consequently it is inconvenient to reach the fitting. Further, it is necessary to stop the vehicle wash while the greasing operation is being performed, thereby increasing the downtime of the vehicle wash.
But, using grease within a grease fitting and spherical rod end may result in grease dripping upon the vehicle passing thereunder. The curtains may then actually rub grease into the vehicle, hindering the vehicle cleaning process. Therefore, care must be taken to provide only limited amounts of grease to the spherical rod end.
To avoid the above problems, an alternative lubrication method has been used which includes spraying water externally upon the spherical rod end as the crank arm rotates. A problem associated with this method is that spray striking the spherical rod end spreads over adjacent components of the car wash, which are generally metallic, increasing the rate at which these components rust and reducing their working lives. Also, if the spray is not accurately directed, adequate amounts of water may not be received between the ball-race surface interface with the spherical rod end thereby increasing the possibility of friction and noise because of the lack of lubrication.
The present invention addresses the aforementioned problems.